Process for the continuous purification of crude carbon disulphide



Spt. `17, 1929. E. LEGE-LER Er AL 1,728,686

PROCESS FOR THE CONTINUOUS vPURIFICTI'ON OF CRUDE CARBON DISULPHIDE Filed Dec. 7, 1925 Eef/ux a F /lodre C52 Va/oons selmann j WMM/Z 4through D. It is also ossible to insert a lcarbon disulphide recti Patented Sept. 1"?,y 1929 maaar UNITED STTES PATENT OFFICE EBERHABD LEGELEN. AND PAUL EssELMANN, or PaEMNITz, WEsTrLAvELLAND, cna- MANY, AssIcNoas To L c. FARBENINDUSTRTE AKTIENGESELLSCHAFT, yor FRANK,-

FonT-oN-THE-MAIN, GERMANY, A CORPORATION oF GERMANY IPBOGESS FOB THE CONTINUOUS PURIFICATION 0F CRUDE CARBON DISULPHIDE Application led December 7 1925, Serial No. 73,926, and in Germany July 6, 1925.

This invention relates to improvements in or modifications of the process for the continuous purification of crude carbon d1- sulphide disclosed in Patent No. 1,672,948, granted June 12, 1928. According to claim 1 of the said specification the'carbondisulphide is freed from hydrogen sulphlde by counter-current contact with carbon disulphide vapours, after which the sulphur and sulphur compounds are i withdrawn from the carbon disulphide in the form of a highly concentrated solution, for example by chemical purification by means of lyes or acids. l

It has now been found that the 'sequence indicated in the case of the above process is not unconditionally necessary for attaining success. Even in the vessel in which the hydrogen sulphide is removed by counter-current contact with carbon disulphide vapours it is possible in the lower part of the column to draw ofi' the carbon disulphide vapours which are completely ree from hydrogen sulphide and after condensation oi' these vapours a carbon disulphide is obtained which by purification with lye or acid now accrues in a completely pure form.

In the accompanying drawing Figs. 1 and 2 show two forms of apparatus suitable for carrying out the invention are diagrammatically illustrated in sectional elevation. The method of working of the tower illustrated in Fig. 1 corresponds in general to that indicated in U. S. patent application Serial No. 22,981, only a concentrated solution of sulphur in carbon disulphide accumulates gradually at C, as carbon disulphide vapours are continuously withdrawn through F and condensed in a cooler Gr, the concentrated solution being withdrawn from time to time or continuously 'ng column in the hydrogen sulphide expelling column,l as shown in Fig. 2' the said rectiying column being filled for example with Raschig rings or the like and in this column is then also obtained at ythe same time a rather thorough,freeing of the carbon ,disulphide from volatile liquid compounds which. in

possible to allow the aforementioned inserted carbon disul hide rectifying column to extend down as ar as the liquid surface level of the carbon disulphide in the hydrogen sulphide expelling column in order for example to prevent any priming of hydrogen sulphide. In the lower part of the column there is then located, as previously described, the highly concentrated solution of sulphur in carbon disulphide, which is continuously drawn oi'in a known manner. The carbon disulphide vapours thus liberated are passed back again into the apparatus or separately condensed and recovered.- The method of workin of such a tower which is illustrated in Flg. 2 is as follows.

The trickling or rectifying tower B provided with illing bodies is surrounded by a distilling column F which likewise contains filling bodies and which extends right down to the point y, within the accumulated carbon disulphide orit may determinate above the' surface level of said liquid. The crude carbon disulphide is admitted Athrough A y and is freed from hydrogen sul hide as described in the prior application I'by the pure carbon disulphide vapours ascending from the bottom of the tower which is surrounded with a heating jacket. yThe hydrogen sulphide escapes through a cooler E, which at the same time has :to condense the carbon disulphide vapours carried alongvwith the hydrogen sulphide and return them to the column. The enclosing columnF withdraws pure carbon disulphide vapours, which during their long travel while ascending through the filling bodies are still further rectified and accordingly freed from all foreign substances. The vapours escaping through the tube G are as usual condensed in a cooler. Here again a concentrated solution of sulphur in carbon disulphide gradually Vaccumulates at C and is continuously draw/ of through D.

It is of course also ossible irst to evaporate carbon disulphi e with hydro en sulphide in a distillation retort or st' and to draw ofi out of the said retort the aforementioned concentrated solution of sulphur vin carbon disulphide, although this process has the disadvantage that the hydrogen sulphide is readily dragged along through the whole of the remainder of the apparatus.

Having now particularly described and ascertained the nature of our said invention andin what manner the same is to be performed, we declare that what we claim is a -1. A process for the urification of crude carbon disulphide containing ILSl and other sulfur bodies which comprises introducing the liquid crude carbon disulphide into the upper part of a rectification column, heatin the solution which collects at the bottom o the column, reluxing the mixture of carbon disulphide vapors and sulfuretted hydrogen escaping from the upper part of the column, withdrawing purified carbon disulphide vapors from a lower part of the column, condensing the same, and withdrawing a concentrated solution of sulfur and sulfur compounds from the bottom of the column.

2. A process for the purification of crude carbon disulphide'containing HZS andother sulfur bodies which comprises introducing the liquid crude carbon disulphide into the upper part of a rectification column, heating the solution which collects at the bottom of the column, refluxing the mixture of carbon disulphide vapors and sulfuretted hydrogen i escaping from the upper part of said column,

withdrawing purified carbon disulphide vapors from a lower part of said column, assing vapors through a second column whic encloses the first-named column, withdrawing the vapors from the upper part of the second column, condensing the said vapors and withdrawin a concentrated solution of sulfur and sul r compounds yfrom the bottom of the column.

3. A rocess for the purification of crude carbon p isulphide contalning HZS and other sulfur bodies which comprises introducing the liquid crude carbon disulphide into the upper part 0f\a rectification column, heatin the solution which collects at the bottom o the column, refluxing the mixture of carbon disulphide vapors and sulfuretted hydrogen escaping from the upper part of the column, withdrawing purified carbon disulphide vapors from a lower part of the column, and 'withdrawing a concentrated solution of sulfur and sulfur compounds from the bottom of the column.

In testimony whereof we have signed our names to this specification. p DR. EBERI-IARD LEGELER.

DR. PAUL ESSELMANN. 

